Performance Analysis Of High Temperature Pressure Sensor Under Comprehensive Environmental Stress

With the development of science and technology,SiC high temperature pressure sensors have become more and more widely used in petroleum,automotive and aerospace applications,and their role has become increasingly important.In recent years,more and more scholars at home and abroad have begun to pay attention to their output characteristics.However,the research on the output characteristics of SiC high temperature pressure sensors is mainly conducted under single environment,and mainly focuses on the sensitivity and linearity,and the zero drift is rarely involved.Therefore,the performance analysis of the high temperature pressure sensor under the comprehensive environment is of great significance to the application and development of the sensor.In this paper,the sensitive structure of the SiC capacitive high temperature pressure sensor for untouched and touched is firstly modeled,on the basis of the sensitive structural model of the untouched and touched SiC capacitive high-temperature pressure sensor,analyzed the capacitance Components and derivation of the output capacitance formula.Based on the ANSYS finite element analysis software,the simulation methods for the untouched and touched states of the SiC capacitive high temperature pressure sensor under integrated environment were studied,especially for the contact state of the SiC capacitive high temperature pressure sensor,the importance of the contact pair and the implementation steps through relationship of contact guidance or element to create contact pairs was analyzed.Based on the simulation method of the SiC capacitive high temperature pressure sensor under the comprehensive environment,the determination method of the center deflection under untouched state and the contact radius under the touched state is analyzed.The center deflection and contact radius under seven kinds of temperature loads in the range of 25°C-600°C and ten kinds of pressure loads in the range of100KPa-2MKPa were simulated.Based on the output capacitance formulas under the untouched and touched states.The output capacitance changes with temperature and pressure were derived and analyzed.The results show that:In the untouched state,the output capacitance increases nonlinearly as the applied pressure increases.As the temperature rises,the cavity height decreases,and the capacitance of the cavity increases as the cavity height decreases.This leads to the increase in the total output capacitance of the capacitive high temperature pressure sensor under constant pressure when the temperature increases.In the touched state,the output capacitance of the capacitive high temperature pressure sensor increases,and as the pressure increases,the speed of the output capacitance increases first and finally unchanged.It remains basically unchanged.In order to study the influence of structural parameters of SiC capacitive high-temperature pressure sensors on the capacitance output,sensor sensitive structural models with different cavity heights,thickness of pressure sensing films,and SiO₂ layer thicknesses were established.The influence to the sensitivity,linearity,and zero drift were studied,respectively.In summary,the modeling and simulation methods for capacitive high temperature pressure sensors untouched state and touched state are studied in this paper.The output capacitance formulas under these two working conditions are deduced respectively,and the output capacitance changes with external loads in an integrated environment was studied.For the evaluation technology research,the performance of the sensor under untouched and touched state was analyzed through the three aspects of linearity,sensitivity and zero drift,and the influence with the change of sensor structure parameters on them was simulated and calculated.